The Pincushion Urchin has an oval to round body covered with hundreds of uniform spines. Its color can range from red to purple to white and blue.
It requires ample hiding places and sufficient room in which to forage in the home aquarium. It generally hides in caves during the day, though it may make a burrow in thick substrates. At night, it comes out to graze on algae, moving about by its suctorial podia that are aligned in five doubled rows. The aquarium should include large amounts of live rock on which it can graze. It may also prey on some of the sessile invertebrates in the reef system. Rock formations need to be stable and able to withstand the movement of the Urchin wedging itself in crevices. It is generally solitary, but will tolerate others of its own kind. It is sensitive to high levels of copper-based medications and will not tolerate high nitrates. Poor water quality will cause it to lose its spines.
It is extremely difficult to breed in an aquarium, with no distinguishing characteristics to help differentiate it from its mate.
If there is insufficient algae for it to graze on, the diet should be supplemented with dried seaweed.